WASHINGTON — Another day, another bailout. The U.S. government stepped in Tuesday to rescue American International Group, one of the world's largest insurers, with an $85 billion injection of taxpayer money.

It was the second time this month the feds put taxpayer money on the hook to rescue a private financial company, saying its failure would further disrupt markets and threaten the already fragile economy.

AIG said it will repay the money in full with proceeds from the sales of some of its assets.

Under the deal, the Federal Reserve will provide a two-year $85 billion emergency loan to AIG, which teetered on the edge of failure because of stresses caused by the collapse of the subprime mortgage market and the credit crunch that ensued. In return, the government will get a 79.9 percent stake in AIG and the right to remove senior management.

The move was similar to government's seizure on Sept. 7 of mortgage giants Fannie Mae and Freddie Mac, where the Treasury Department said it was prepared to put up as much as $100 billion over time in each of the companies if needed to keep them from going broke.

The Fed said it determined that a disorderly failure of AIG could hurt the already delicate financial markets and the economy.

It also could "lead to substantially higher borrowing costs, reduced household wealth and materially weaker economic performance," the Fed said in a statement.

The decision to help AIG marked a reversal for the government from the weekend, when it refused to use taxpayer money to bail out Lehman Brothers Holdings. Lehman, which filed for bankruptcy Monday, collapsed under the weight of mounting losses related to its real estate holdings. The White House said it backed the Fed's decision Tuesday.

"These steps are taken in the interest of promoting stability in financial markets and limiting damage to the broader economy, " White House spokesman Tony Fratto said.

After meeting with Treasury Secretary Henry Paulson and Fed Chairman Ben Bernanke in a late-night briefing on Capitol Hill, Congressional leaders said they understood the need for the bailout.

"The administration is approaching an unprecedented step, but unfortunately we are living in unprecedented times. Hearing of these plans, you have to stop to catch your breath. But upon reflection, the alternatives are much worse," said Sen. Charles Schumer, D-N.Y.

In a statement late Tuesday, AIG's board of directors said the loan will protect all AIG policy holders, address concerns of rating agencies and buy the company time to sell off assets.

"We expect that the proceeds of these sales will be sufficient to repay the loan in full and enable AIG's businesses to continue as substantial participants in their respective markets," the statement said.